Do you want to understand autoimmune diseases better? How does the human immune system work?
Before anyone can learn how to prevent or reverse autoimmune diseases, it’s important to first understand what they are and how they originate. Amy Myers, a functional medicine physician and former emergency room doctor, explains this in her book The Autoimmune Solution.
Continue reading for an explanation of how your immune system can turn autoimmune.
How Autoimmune Diseases Work
In her book The Autoimmune Solution, Dr. Amy Myers explains that autoimmune diseases are conditions where your immune system attacks your body as if it were a threat.
We’ll share Myers’ explanations of how your immune system works, how it can become dysregulated, and how that dysregulation can lead to autoimmunity. Finally, we’ll discuss how visualizing autoimmunity on a continuum can help you understand autoimmune diseases.
How a Healthy Immune System Works: Acute Inflammation
Your immune system protects your body from harmful invaders like bacteria, viruses, and parasites. Myers explains that your immune system uses physical barriers like the skin and mucus, as well as specialized cells and antibodies that identify and neutralize threats.
(Shorform note: Your immune system’s multilayered defense ensures that if one mechanism fails, others can compensate. This helps your system provide robust protection against a wide range of pathogens. It also allows your immune system to evolve and improve its responses over time, as different components can be fine-tuned based on your body’s experiences with various infections.)
When your immune system identifies a threat, it launches a response: acute inflammation. This is a normal, healthy response to specific threats, like an injury or the flu. Myers says that it manifests as responses such as redness, swelling, fever, and pain, and the response stops once the threat is gone.
Myers describes the two main components of your immune system:
- The innate immune system activates immediately when it detects a threat. It launches an inflammatory response to flood the threat with blood and other fluids that neutralize it.
- The adaptive immune system “learns” from the threats your body has neutralized and creates targeted antibodies to defend against the same threats in the future.
According to Myers, your body needs both immune system components to protect you in the short and long term.
| The Immune System: A Delicate Balance Although your immune system tries to protect you in the short and long term, it can sometimes make healing or preventing illness more challenging. For example, scientists studying the coronavirus discovered that a patient’s fate depended largely on their immune system. When the virus enters someone’s body, their immune system launches an inflammatory response that causes mild symptoms such as congestion and body aches. After several days, some patients start to feel better, while other patients’ immune systems kick into overdrive to stamp out the virus. Why do some patients’ immune systems go into overdrive? When the innate immune system launches this attack, too much inflammation can lead to permanent organ damage and death. The patient has a sudden, dramatic decline, which can entail a racing heart, shortness of breath, hallucinations, and organ failure. These responses are more severe than the types of acute inflammation Myers describes. At this point, doctors have to walk a fine line between limiting the harm from the virus and the harm from the body’s immune response. While an overactive innate immune system can make it harder to heal, the adaptive immune system makes it possible to prevent new infections—up to a point. In some cases, people gain lifelong immunity after a viral infection, but this isn’t always the case. |
When Your Immune System Becomes Dysregulated: Chronic Inflammation
Although an active immune system is crucial for health, if it’s too active, it can lead to health problems. Myers argues that your immune system becomes overwhelmed when it faces constant challenges such as poor diet, environmental toxins, infections, and stress. Instead of responding to specific threats with acute inflammatory responses, your immune system is constantly activated, resulting in chronic inflammation.
Myers explains that chronic inflammation can set the stage for autoimmune conditions. Your innate immune system becomes exhausted from battling constant threats to your health. Your adaptive system gets overworked and “confused” as it begins creating antibodies for substances it doesn’t need to fight. This can cause your body to develop new sensitivities or allergies because your immune system overreacts and mounts full-blown defenses against harmless substances, such as lactose.
(Shortform note: Chronic inflammation is linked to health problems other than autoimmune conditions, allergies, and intolerances (such as lactose intolerance). It’s associated with oxidative stress, which can damage DNA, proteins, and fatty tissue, accelerating aging. Chronic inflammation is also linked to cardiovascular, gastrointestinal, metabolic, and neurodegenerative diseases, mental health disorders, and several forms of cancer. However, it’s not entirely clear whether inflammation actually causes these diseases or just accompanies them. Because chronic inflammation can persist for a long time, it’s somewhat hard to tell whether it increases the risks of these diseases or whether it’s a byproduct of the processes that cause these diseases.)
In extreme cases, your immune system can mistakenly identify your body’s organs or fluids as threats, leading to autoimmune conditions. For example, in people with Hashimoto’s disease, their immune system attacks the thyroid. In people with multiple sclerosis, the immune system targets the myelin around nerves.
(Shortform note: A still more extreme case is that of poly-autoimmunity—when the same person develops multiple autoimmune diseases. For instance, researchers found that people with multiple sclerosis are more likely to also develop Hashimoto’s disease and psoriasis, another autoimmune condition.)
The Autoimmune Continuum
Myers argues that there isn’t a specific point where a healthy immune system becomes so dysregulated that it creates an autoimmune condition. Instead, she believes people fall along an autoimmune continuum. This continuum includes those who experience mild to moderate symptoms and those with a full-blown autoimmune diagnosis. She describes the following parts of the continuum:
- At the lower end of the continuum are people who sporadically experience an individual symptom that might signal underlying inflammation, such as digestive issues or difficulty focusing. These people are at risk of developing autoimmunity.
- In the middle of the continuum are people who have around three symptoms that occur frequently, such as several times a week. Their risk of developing autoimmunity is higher.
- Near the higher end of the continuum are people who experience symptoms every day. They likely already have an autoimmune condition, but they haven’t received a diagnosis yet.
- At the higher end of the continuum are people who have an autoimmune diagnosis.
Although the continuum shows a worrying progression, Myers believes it’s a helpful way to frame autoimmunity. Why? It suggests that early intervention can make a difference in the evolution of a disease. Because autoimmunity develops gradually, there are opportunities to notice symptoms and take action to reverse the disease.
(Shortform note: Despite this benefit of the autoimmune continuum, it may oversimplify complex autoimmune disorders that don’t always follow a linear progression. For instance, some patients may develop full-blown autoimmune conditions without experiencing stages earlier in the continuum. Additionally, the autoimmune continuum could lead people to misinterpret their mild symptoms as predictive of a more severe outcome, possibly causing unnecessary health anxiety.)
